I know it’s possible to enable the Coverage Sampled AA through the control Panel.
It’s also possible to create a FBO with Coverage Sampled AA with the extension GL_NV_framebuffer_multisample_coverage.
However, I dont want to create a FBO. I just want my application to decide the level of MSAA/CSAA on the back buffer with the function wglChoosePixelFormatARB. Is there any way to do that in OpenGL?
Read that extension paper. It’s similar to MSAA FBOs:
http://developer.download.nvidia.com/opengl/specs/GL_NV_framebuffer_multisample_coverage.txt
I think this extension only works with FBOs not with the default back buffer?
It looks like thwer is currently no other way than rendering into a FBO. http://developer.download.nvidia.com/SDK/10/direct3d/Source/CSAATutorial/doc/CSAATutorial.pdf
A disadvantage is the double blitting from the CSAA render target to a texture and from the texture to the backbuffer (but it can be used for a postfilter)
The only alternative seems to be to create an MSAA rendertarget and extend it with the controll panel.